Sheet separating apparatus

ABSTRACT

Apparatus for separating layers of limp fabric from a stack, including an angular lifting needle and a second, upright, needle. The lifting needle typically penetrates the top layer and then lifts it onto the second needle. The separated layer, secured on the needles, is transported to a work station where castoff means serve to disengage the fabric from the needles. By adjustment of the lifting needle, more than one layer can be separated from the stack in a single operation. An additional element may be used to physically restrain the stack from moving up with the ply to be separated.

United States Patent Kenneth 0. Morton [72] Inventor 793,009 6/1905Miller 271/18 T N Y, 1,394,202 10/1921 Leumann 271/26 [21} Appl. No.854,225 2,003,698 6/1935 Remington 271/25 [22] Filed Aug. 29, 19692,374,838 5/l945 Russell et a1 271/29 [45] Patfmted 1971 PrimaryExaminer-Joseph Wegbreit [73] Ass'gnee Chen Peabody Anorneys- LeoFornero and Robert J. Dockery Troy, N.Y.

[54] SHEET SEPARATING APPARATUS 11 Claims 14 Drawing Figs. ABSTRACT:Apparatus for separatlng layers of limp fabric from a stack, includingan angular lifting needle and a second, [52] [1.5. CI 271/18 upright,needle. The lifti needle typically Penetraes the top l B651 3/22 layerand then lifts it onto the second needle. The separated [50] Field ofSearch 271/18, 21, layer, Secured on the needles, is transported to awork station 19 where castoff means serve to disengage the fabric fromthe needles. By adjustment of the lifting needle, more than one [56]References cued layer can be separated from the stack in a singleoperation. An UNITED STATES PATENTS additional element may be used tophysically restrain the stack 142,822 9/1873 Thian 271/18 from moving upwith the ply to be separated.

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w z ATTORNEY SHEET SEPARATIING APPARATUS BACKGROUND OF THE INVENTION Thefield of the present invention is ply separation and more particularlyseparation of one or more layers of porous material from a stack. Theinvention is particularly useful in separating a layer of fabric from astack of many pieces. Particular problems presented by fabric pieces arethat they are limp;

porous and are often cut in such a way that the layers are boundtogether at the edges by the cutting. Vacuum systems have been used toseparate sheets of paper from a stack but are generally consideredunreliable for separating cloth pieces because of the porosity of cloth.Needles have been used to deliver fabric plies from a stack one at atime. One such arrangement is shown in US. Pat. No. 3,406,961. Anotherdevelopment is illustrated in U.S.- Pat. No. 3,386,763and utilizesangled pins which are urged into the fabric by means of inflatableelements disposed in the pickup head.

These latter mentioned methods are an improvement over vacuum for themost part; however, they tend to pick up or deliver more than one plydue to the tendency of the plies to cling to each other, particularly attheir cut edges. the problem is made simpler by initially dissociatingthe layers after cutting; but in a manufacturing operation this is anexpensive proposition, and there is a need for an apparatus which candeliver sheets one at a time directly from the stack as cut. The problemof edge clinging is particularly acute where heated blades are used tocut fabrics having thermoplastic threads since the'threads fuse togethermaking discrete separation of plies difficult.

SUMMARY OF THE INENTION The present invention overcomes variousdisadvantages found in prior art devices. In the invention, lifting andlocking needles are used in conjunction with an element which has beentermed a holddown finger. The complete apparatus might utilize severalpickup heads or modules operating on the material at different points toachieve an even lifting.

Pressure from a picking or lifting needle is brought to bear against thetop sheet of material. This needle is meant to penetrate only the topply if only that ply is to be picked up. The sheet caught by the liftingneedle is then typically penetrated by a set of two locking needles,disposed on either side of the picking needle, as the picking needle israised in .relation to the locking needles. This action pushes away allbut the sheet that is engaged by the picking needle. A cavity is nowformed locally at the needles between the top sheet and the rest of thestack. A holddown finger is inserted in the cavi ty to hold theremaining plies as the top ply is pulled away. The

top sheet is then moved to a work station or a separate delivery meanssuch as a belt feed. The material is disengaged from the pickup heads bydrawing back the picking needle and pushing the sheet off the lockingneedles.

A primary feature of the invention is that it will separate a selectednumber of sheets effectively and efficiently with the requiredreliability. The invention may be used to separate sheets ofvaryingporosity.

Another feature is that the separated sheets may be delivered to aworking station at a point away from the stack.

THE DRAWINGS The invention will be more easily understood with referenceto the drawings whereini FIG. 1 is a view of a pickup module partiallyin section;

FIG. 2 is a plan view of a lever arm holding picking needles;

FIG. 3 is an elevation ofthe lever ofFIG. 2;

FIG. 4 is a plan view of the module of FIG. 1;

FIG. 5 is a side elevational view of the module of FIG. 1; FIG. 6 is adetail showing a sheet being separated from a stack;

FIGS. 7a and 7b are views of a typical picking needle;

FIGS. 80 and 8b are views of a typical. locking needle;

FIGS. 9a and 9b are views of a holddown mechanism;

FIG. 10 is a side elevational view of an apparatus employing several ofthe modules of FIG. 1; and 1 FIG. 11 is a plan view of the apparatus ofFIG. 10.

The drawings should be understood to be more or less of a schematicrepresentation. Like numerals identify like elements in the severalviews.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows a picking moduledesignated as M which includes lever arm 10 pivotally mounted on crank11 at pin 12. The crank is secured to a plate 14 by pin 15 so that thecrank is free to rotate about the pin. A spring 17 is carried in housing18 at an end and engages a notch 19 in the crank arm. The spring isshown under partial compression so that crank 11 will tend to rotateclockwise about pin 15 unless restrained in some fashion. Since arm 10floats on the crank at the end opposite the spring, the entire lever arm10 will move generally to the left (as seen in the drawing) as the crankrotates clockwise and will move generally to the right as the crankrotates counterclockwise. The motion of arm 10 is controlledadditionally by spring 20 which exerts a downward force on the workingend of the arm, by stop 21 and by actuator 22. The whole assembly ismounted between plate 14 and a second plate which is not shown in thedrawing.

When the bearing surface 23 of the assembly, which is formed by thebottom-most edge of the plates and the housing,

. is held stationary the actuator is free to move up and down in .10 asthe actuator moves up and down. The actuator arm restrains the crankfrom rotation when in its up position and in its downward traveloperates to swing the working end of the lever arm 10 up by reason-0fthe rotation of the lever about its 7 pivot 12.

Referring now to FIG. 2, two picking needles designated as 30 are shownlocated in the working end of the lever arm 10. Alternately a singlepicking needle or a plurality of needles could be used. The needles areclamped in place by clamp portion 31 which is held by bolt 32.

FIG. 3 shows the shape of the clamp portion of the lever. Preferably anopen throat 33 is formed between the needle and the clamp portion. Thisthroat may typically be formed by cutting back the part of the clampnear the head of the picking needles. The throat allows the fabric beinglifted to ride up on the needle without restraint, thereby reducing thetendency of the needle to tear the threads of the fabric. A cavity 34may be included in order to prevent lint from collecting in the throatand to further prevent any restraint on the fabric other than thatprovided by the penetration of the needles. It has been foundadvantageous to have the throat clearance about onehalf the thickness ofthe plies being separated. The lever should be so shaped that there arebearing surfaces 35a and 35b in front and in back of the needles. Thesesurfaces serve to flatten out any puffing of the plies of fabric in thearea of the needles which might be caused by the action of surface 23(FIG. 1) as the latter surface is urged down against the stack of fabricsheets. In the discussion, reference will generally be to a situationwhere only a single ply is separated from a stack as this is the usualcase, however, several plies can be picked simultaneously if it isdesirable to do so in a particular instance. The number of pliesseparated will depend upon the amount the picking needles extend beyondthe bearing surfaces 35a and 3511.

FIG. 4 illustrates the disposition of a second set of needles 36utilized in the picking module. These needles cooperate with the pickingneedles and are termed locking needles because they assist in holdingthe separated ply during carriage of the ply from the stack to a newposition. The locking needles are spaced far enough apart that the lever10 with its picking needles can move up and down between the lockingneedles and are secured to the module by clamp 53 which defines aU-shaped slot 52 (FIG. 1). The locking needles serve additionally todiscourage picking of more than the desired number of plies.

FIG. 5 shows the picking module with both face plates in place and withthe lifting lever arm in a down position. Actuator 22 is up and thehidden (or back) end of the lever 10 is resting against the stop 21(FIG. 1). This is the normal position of the lever prior to picking.

The figure shows a trip mechanism which includes two trip levers 40a and40b carried on a bushing located on the hous- 7 ing. Lever 40a actsagainst a pin 41 pressed into a hole in the crank. Upward movement of40a causes a counterclockwise rotation of the crank, which in turn pullsthe lifting needles to the right. This action is utilized to disengagethe picking needles from the fabric and willbe discussed later inrelation to operation of the module. Lever 40b includes a cam 42 whichacts against latch 25 to cause the latch to disengage the actuator 22,allowing spring (FIG. 1) to push the picking needles downward asactuator 27 is forced upward by the action of the actuator spring. Thedownward movement of the bearing surfaces 35 provides a means of castingoff the ply from the locking needle after the lifting needles have beendisengaged from the fabric.

The operation of the module may be better understood with reference to adescription of the interaction of the various elements during a pickupand castoff sequence. Referring now to the drawings discussedhereinbefore and particularly to FIGS. 1 and 5, the module is broughtdown against the top ply F ofa stack of fabric sheets with the pickingneedle being the first part of the module to touch the top sheet or plyof fabric. This may be accomplished by letting the lever arm carryingthe needle extend slightly below bearing surface 23 as depicted in HQ 5.Since the picking needle is on the end of a pivot arm with a pivot pointabove the needle when the needle first engages the fabric, there is, inaddition to upward movement, a slight forward (to the left in thedrawing movement which assists in providing a good pick. The bearingsurface of the module then Comes to rest against the stack and serves tohold the stack in place against the force exerted by the picking needlewhich now starts a movement to the left as the movement of the actuator22 allows crank 11 to rotate clockwise. The picking needle, havingengaged the layers to be separated, will move upward as the actuator onwhich the module is carried is pushed down against the lever 10. The topply is now securely on the picking needle and is pulled up and onto thelocking needles.

The preferred movement of the picking needle is first generally down andagainst the stack and then with a component of movement generallyparallel to the stack and finally upward. The main problem is to havethe angled picking needle penetrate to the desired depth depending onhow many layers of fabric are to be separated from the stack. Thepicking needles might, for example, be initially pushed into the clothin a direction along the axis of the needle shaft until the desiredpenetration is achieved and then moved up and away from the stack.

There may be a slight movement of the picking needle away from thelocking needle as the picking needle lifts in order to create tension onthe cloth between the needles which will more securely lock the sheet onthe needles Another way of encouraging a slight tension is to angle thelocking needles such that, as the cloth rides up the needle, it iscarried away from the lifting needle.

Preferably the locking needles do not extend down to the level of thebearing surface 23. It is desirable that on the downward movement of themodule the locking needles do not engage any of the other plies as thiswould interfere with the action of the picking needle and might causeundesirable localized stretching in holding the fabric against theforward motion of the picking needle when the picking needle firstengages the top ply. Additionally, the locking needles are held abovesurface 23 to prevent them from being forced through sheets of fabricwhich are not to be separated on the particular cycle. Should thelocking needles initially engage sheets other than those to beseparated, their ability to push away unwanted layers would be impaired.

Referring now to FIG. 6, when the picking needle is fully raised thefabric is disposed as shown in FIG. 6, being held securely in place onthe needles. The latch 25 (FIG. 1) locks the actuator arm down which inturn secures the picking needle in the up position.

The needles used may have a variety of shapes, however, certain shapesare preferable. FIGS. 7a and 7b show the preferred shape for the pickingneedle (or needles). The needle is ground to a fine point and has a flattriangular shape on either side. The needle should have a flat top sidein order to form an even throat dimension when installed in the clamp ofthe picking lever. The bottom of the needle exhibits a very then portion70 which creates a shoulder 71. This shape allows a minimum resistanceto penetration of the needle up to the shoulder which then providesabruptly a greatly increased resistance to further penetration. Thus,the shape of the picking needle may be utilized to assist in obtainingthe desired picking characteristics. The amount of diagonal penetrationis controlled by the restrictive shape of the picking needles and/or bythe extension of the needle beyond surface 35b.

Referring now to FIGS. 8a and 8b, the locking needle (or needles) has aflat top like the picking needle but has a gradually sloping bottomsurface 72. When the picking needle engages the top ply and begins toraise it, the ply is stretched somewhat so that there is some loosenesscreated about the point where the locking needles first engage thefabric. Therefore, the top ply will more easily move up the lockingneedles then will lower plies and so the locking needles serve theadditional function of discouraging picking of more plies than areengaged by the picking needle.

Although the module previously described may be utilized alone, for manysituation an additional element may be used in conjunction with thepicking module to assure that only the desired number of plies will beseparated from the stack.

When fabric plies are to be separated from a stack which has been diecut, there is a pronounced tendency of the plies to stick together atthe edges. In such a situation, the picking module can successfullyseparate the plies at a point away from the edge but the edges mayremain stuck, making it difficult to transport only the top ply awayfrom the stack, especially without disturbing the stack.

A second element termed a holddown finger may be utilized to aid inobtaining positive ply separation even when the edges stick together.Referring now to FIGS. 9a, 9b, 10 and 11, the holddown finger 50 isconnected to a suitable actuating mechanism designated generally as 51.Preferably the finger is mounted with some play up and down throughspring pressure so that it can engage the slot 52 formed by the clamp 53which secures the locking needles. (FIG. 1).

One method of mounting the holddown finger is illustrated in FIGS. 9aand 9b. The finger 50 rides in slot on roller 81 and cam 82. A link 83is attached to piston 85. As the piston 85 extends, the link attached tocam 82, urges the finger up and back. The upward movement is stoppedwhen the cam 82 bears on the top edge of the slot 80. When the piston 85retracts, the finger moves out and down, passing through the U-shapedslot 52 formed in the clamp 53. (See FIG. I).

In instances where the finger may have to go through a seam formed atthe cloth edges by fusing or entanglement of the fibers during cutting,the locking needles will act to keep down all but the picked sheets. Thefinger may actually turn back the plies before it breaks the edge seam,but this will cause no problem since the finger will simply be urgedinto the cavity formed between the picked ply or plies and the rest ofthe stack.

Referring back to FIG. 1, a slotted cap 105 is screwed to the top of theactuator 22. The leg of an L-shaped arm extends into the slot of the capat one end and is swingably attached at its other end to mountingbracket 86. A spring :91 provides I sufficient tension to keep key 90sin engagement with slot 22s.

respective actuators 22 by virtue of the position of rods 92 in relationto the top of the actuator. As the pistons of cylinders 102 extend, therods 92 push the actuators down. The rods are so located that at thepicking station, the actuators are unlocked and are free-to move up anddown, the rods having pushed arms 90 (FIG. 1) to the left as the modulesmove to the right and into position for pickup. The modules move downuntil they come to rest against the stack F after which the ac tuatorscontinue downward, causing the lever arms 10 (FIG.

1') to lift. Once the separation is accomplished and the top ply issecurely on the needles, the cylinders 102 retract and pull the modulesup. When the modules are fully raised the indexing belt 103 moves,carrying the modules laterally toward the discharge station. Thespring-actuated locking arm 90 (FIG. 1) secures each module in the upposition of transport to the discharge station. I

Castoff at the discharge station is accomplished when trips 104 actuatearms 40b (FIG. .5) causing the trip levers 40a to contact and rotatecrank pins 41 clockwise thereby disengaging the picking needles andcausing the picking levers 10 to snap down so that the fabric is pushedoff the locking needles. The lower arms 40b are similarly actuated bytrip 104 when the modules are mounted in a position 180 from that shownin FIG. 5.

FIG. 11 is a plan view of the pickup and discharge stations 100 and 101The figure shows one possible arrangement of modules to lift a largepiece. Four modules are used, one near each corner. The figure alsoshows the location of the holddown fingers 50 in relation to themodules.

Means may be provided as shown in FIG. 10, to maintain the stack at aparticular level as layers are removed. Rack 106 and pinion 107,connected to motor 108 operate platform 109 such that the level of thetop layer of the stack remains constant as pieces are picked from thestack.

' It will be appreciated from the foregoing that-there are a variety ofways of achieving the interaction of the various parts described and itwill be appreciated that a wide variety of changes may be made withoutdeparting from the scope of the invention. For example, certain featuresof the apparatus may be used independently of others and equivalents maybe sub- .stituted for the various elements and steps all within thespirit and scope of the invention.

Iclaim:

1. Work handling apparatus for separating a predetermined number ofsheets from a stack of many sheets, comprising in combination: a pickingneedle for engaging and lifting said predetermined number of sheets awayfrom the stack; and a locking needle projecting generally verticallytoward the top surface of the stack and located in the vicinity of thepicking needle such that the predetermined number of sheets lifted awayfrom the stack by the picking needle is carried up the locking needle bythe upward movementof the picking needle.

2. The method of separating a predetermined number of sheets from astack of many sheets including the steps of lifting only thepredetermined number of sheets from the stack on an 3. Work handlingapparatus for separating a predetermined number of sheets from a stackof many sheets, comprising in combination: a picking element having atleast one picking needle projecting therefrom; means for moving theelement with respect to the stack first generally downwardly and thenwith a component of movement substantially parallel to the stack suchthat the needle engages at least the predetermined number of sheets, andthen away from the top surface of the stack, to lift said predeterminednumber of sheets away from the other sheets in the stack; at least onelocking needle projecting generally downwardly toward the top surface ofthe stack and located in the vicinity of the picking needle such thatthe predetermined number of sheets lifted away from the stack by thepicking needle is carried up the locking needle by the upward movementof the picking element; whereby the predetermined number of sheets issecured on said needles by reason of the tension created between thepicking needle and the locking needle.

4. Work handling apparatus for separating a predetermined number ofsheets from a stack of many sheets, comprising in combination: a pickingelement having a needle projecting therefrom at an angle of less thanwith respect to the top surface of the stack; means for moving theelement with respect to the stack first generally downwardly and thenwith a component of movement substantially parallel to the stack suchthat the needle engages at least the predetermined number of sheets, andthen away from the top surface of the stack, to lift said predeterminednumber of sheets away from the other sheets in the stack; at least onelocking needle projecting generally downwardly toward thetop surface ofthe stack and located in the vicinity of the picking needle such thatthe predetermined number of sheets lifted away from the stack by thepicking needle is carried up the locking needle by the upward movementof the picking element; whereby the predetermined number of sheets issecured on said needles by reason of the tension created between thepicking needle and the locking needle.

5. Work handling apparatus for separating a predetermined number ofsheets from a stack of many sheets, comprising in combination: a pickingelement having at least one picking needle projecting therefrom; meansfor moving the element, with the needle disposed at an angle of lessthan 90 with respect to the top of the stack, first generally downwardlyand then with a component of movement substantially parallel to thestack such that the needle engages at least the predetermined number ofsheets, and then away from the top surface of the stack, to lift saidpredetermined number of sheets away from the other sheets in the stack;at least one locking needle projecting generally downwardly toward thetop surface of the stack and located in the vicinity of the pickingneedle such that the predetermined number of sheets lifted away from thestack by the picking needle is carried up the locking needle by theupward movement of the picking element; whereby the predetermined numberof sheets is secured on said needles by reason of the tension createdbetween the picking needle and the locking needle.

6. The'apparatus of claim 3 including means for securing the sheets ofsaid stack from sliding movement at least during the time when themovement of said needle has a component substantially parallel to thetop surface of the stack.

7. The apparatus of claim 3 including means, in addition to any of saidneedles, from restraining the sheets of the stack other than saidpredetermined number of sheets from upward movement away from the stack,and means for inserting said restraining means between said other sheetsand said predetermined number ofsheets during the separating.

8. The apparatus of claim 1 including means for moving the needles,without changing their position relative to each other, laterally to apoint remote from the stack, means for disengaging the picking needlefrom the separated sheets, and means for pushing the separated sheetsoff the locking needle.

9. The method of separating a predetermined number of sheets from astack of many sheets including the steps of lifting only thepredetermined number of sheets from the stack on an angled needle and,during the lifting, drawing the said predetermined number of sheets up asecond needle disposed generally vertically, transporting the saidnumber of sheets to a location remote from the stack, disengaging theangled needle from said sheets and then pushing the sheets offsaidsecond needle.

10. Work handling apparatus for separating a predetermined number offabric sheets from a stack of many sheets comprising in combination: apicking needle for engaging and lifting said predetermined number ofsheets away from the stack; and a locking needle adapted to projectgenerally vertically downward and in the vicinity of the picking needlesuch that the locking needle engages the said sheets only as thepredetermined number of sheets is lifted away from the stack by thepicking needle, and such that the predetermined number of sheets liftedaway from the stack by the picking needle is carried up the lockingneedle by the upward movement ofthe picking needle.

11. Work handling apparatus for separating a predetermined number ofsheets from a stack of many sheets, comprising in combination a pickingelement having at least one needle, means for moving the picking elementfirst generally downward and then with a component of movement which issubstantially'horizontal such that the needle is adapted to engage saidpredetermined number of sheets, and then upward, to lift saidpredetermined number of sheets away from the rest of the stack; at leastone locking needle projecting generally downward and located near thepicking needle such that said predetermined number of sheets is carriedupward against the point of the locking needle.

1. Work handling apparatus for separating a predetermined number ofsheets from a stack of many sheets, comprising in combination: a pickingneedle for engaging and lifting said predetermined number of sheets awayfrom the stack; and a locking needle projecting generally verticallytoward the top surface of the stack and located in the vicinity of thepicking needle such that the predetermined number of sheets lifted awayfrom the stack by the picking needle is carried up the locking needle bythe upward movement of the picking needle.
 2. The method of separating apredetermined number of sheets from a stack of many sheets including thesteps of lifting only the predetermined number of sheets from the stackon an angled needle at a point near an edge of said stack and, duringthe lifting, drawing said predetermined number of sheets up a secondneedle disposed generally vertically to form a cavity near the edge,inserting a restraining element into the cavity to hold down theremaining sheets in the stack, and then completing the separation of thepredetermined number of sheets from the stack by moving both of saidneedles away from the stack.
 3. Work handling apparatus for separating apredetermined number of sheets from a stack of many sheets, comprisingin combination: a picking element having at least one picking needleprojecting therefrom; means for moving the element with respect to thestack first generally downwardly and then with a component of movementsubstantially parallel to the stack such that the needle engages atleast the predetermined number of sheets, and then away from the topsurface of the stack, to lift said predetermined number of sheets awayfrom the other sheets in the stack; at least one locking needleprojecting generally downwardly toward the top surface of the stack andlocated in the vicinity of the picking needle such that thepredetermined number of sheets lifted away from the stack by the pickingneedle is carried up the locking needle by the upward movement of thepicking element; whereby the predetermined number of sheets is securedon said needles by reason of the tension created between the pickingneedle and the locking needle.
 4. Work handling apparatus for separatinga predetermined number of sheets from a stack of many sheets, comprisingin combination: a picking element having a needle projecting therefromat an angle of less than 90* with respect to the top surface of thestack; means for moving the element with respect to the stack firstgenerally downwardly and then with a component of movement substantiallyparallel to the stack such that the needle engages at least thepredetermined number of sheets, and then away from the top surface ofthe stack, to lift said predetermined number of sheets away from theother sheets in the stack; at least one locking needle projectinggenerally downwardly toward the top surface of the stack and located inthe vicinity of the picking needle such that the predetermined number ofsheets lifted away from the stack by the picking needle is carriEd upthe locking needle by the upward movement of the picking element;whereby the predetermined number of sheets is secured on said needles byreason of the tension created between the picking needle and the lockingneedle.
 5. Work handling apparatus for separating a predetermined numberof sheets from a stack of many sheets, comprising in combination: apicking element having at least one picking needle projecting therefrom;means for moving the element, with the needle disposed at an angle ofless than 90* with respect to the top of the stack, first generallydownwardly and then with a component of movement substantially parallelto the stack such that the needle engages at least the predeterminednumber of sheets, and then away from the top surface of the stack, tolift said predetermined number of sheets away from the other sheets inthe stack; at least one locking needle projecting generally downwardlytoward the top surface of the stack and located in the vicinity of thepicking needle such that the predetermined number of sheets lifted awayfrom the stack by the picking needle is carried up the locking needle bythe upward movement of the picking element; whereby the predeterminednumber of sheets is secured on said needles by reason of the tensioncreated between the picking needle and the locking needle.
 6. Theapparatus of claim 3 including means for securing the sheets of saidstack from sliding movement at least during the time when the movementof said needle has a component substantially parallel to the top surfaceof the stack.
 7. The apparatus of claim 3 including means, in additionto any of said needles, from restraining the sheets of the stack otherthan said predetermined number of sheets from upward movement away fromthe stack, and means for inserting said restraining means between saidother sheets and said predetermined number of sheets during theseparating.
 8. The apparatus of claim 1 including means for moving theneedles, without changing their position relative to each other,laterally to a point remote from the stack, means for disengaging thepicking needle from the separated sheets, and means for pushing theseparated sheets off the locking needle.
 9. The method of separating apredetermined number of sheets from a stack of many sheets including thesteps of lifting only the predetermined number of sheets from the stackon an angled needle and, during the lifting, drawing the saidpredetermined number of sheets up a second needle disposed generallyvertically, transporting the said number of sheets to a location remotefrom the stack, disengaging the angled needle from said sheets and thenpushing the sheets off said second needle.
 10. Work handling apparatusfor separating a predetermined number of fabric sheets from a stack ofmany sheets comprising in combination: a picking needle for engaging andlifting said predetermined number of sheets away from the stack; and alocking needle adapted to project generally vertically downward and inthe vicinity of the picking needle such that the locking needle engagesthe said sheets only as the predetermined number of sheets is liftedaway from the stack by the picking needle, and such that thepredetermined number of sheets lifted away from the stack by the pickingneedle is carried up the locking needle by the upward movement of thepicking needle.
 11. Work handling apparatus for separating apredetermined number of sheets from a stack of many sheets, comprisingin combination a picking element having at least one needle, means formoving the picking element first generally downward and then with acomponent of movement which is substantially horizontal such that theneedle is adapted to engage said predetermined number of sheets, andthen upward, to lift said predetermined number of sheets away from therest of the stack; at least one locking needle projecting generallydownward and located near the picking needle such that saidpredetermined number of sheeTs is carried upward against the point ofthe locking needle.